This invention relates to a pre-colored microscope slide for blood investigations.
The differential blood count is one of the most frequently carried out microscopic methods. In this method, the individual blood particles (erythrocytes, leukocytes, thrombocytes, etc.) are selectively stained with dyestuffs which permit a microscopic differentiation and the recognition of pathological changes. The previously employed staining processes, for example those of Wright, May-Grunwald or Pappenheim, involve several steps, for example, preparing a blood smear, fixing, in some cases several stainings, washing and drying and are, therefore, very laborious. Furthermore, the quality of the staining depends very considerably upon the quality of the dyestuffs employed, as well as upon the training and experience of the personnel involved.
Therefore, attempts have already been made in order to simplify these processes. A process has recently been described in German Pat. No. 2,153,673 which makes use of precolored microscope slides which are coated with methylene blue N and cresyl violet acetate. When a drop of blood is applied to such a microscope slide and covered with a cover slip, then microscopic examination can be carried out after about 5 minutes. In this case, in addition to a differentiation of the various forms of leukocytes and thrombocytes, it is also possible to recognize juvenile erythrocytes, i.e. the so-called reticulocytes. Apart from the simplicity and accuracy of use, this is a further advance in comparison with the conventional blood count.
In spite of the undeniable advantage provided by this process, nevertheless it suffers from some serious disadvantages. Thus, the stainings are generally dull, diffuse and lacking in contrast and, in addition, the three different forms of the granulated leukocytes (eosinophils, neutrophils and basophils) can only be differentiated with difficulty.